The molding of parts of intricate shape from various flowable materials, such as plastics, is an old and highly developed art. A typical prior art plastic molding process includes supporting a first mold section and mechanically retaining a second mold section in predetermined relationship to the first mold section. For example, the second mold section may be supported on a large ram so that it can be moved into position for the molding operation and then retracted upon completion of the molding operation. This kind of molding process has the disadvantage of requiring large, heavy and expensive components, such as a ram for carrying out the molding process.
In the manufacture of boats, a sandwich construction comprising a plastic core and opposed panels is utilized. The core material is molded in large, flat sheets. To conform the sheets to the intricate curvature of the panels, the core must be scored a large number of times and, in some instances, heated. The scored and heated core material is then adhered to the panels by placing a flexible sheet over the core and a porous mat between the core and flexible sheet and evacuating the region beneath the flexible sheet. This provides a pressure dfferential across the flexible sheet which holds the core against the panel. This process is expensive and requires considerable time and auxiliary equipment, such as the heating means for the core.